Looking at the hydraulics

[TB2]

Hi.

Gave my good old girl an oil change today and I did so at an offroad garage where a couple of friends in Hamburg are working. I was allowed to use their lifts and tools and such Gave me a chance to take a proper look under the car. I was really surprised how _many_ of those pipes there are. It's full of them, they're everywhere. Like 4 at each side running back (well, makes sense, two for the suspension, two for the brakes huh). I found one spot where the pipes are increasingly rusty, and two spots where there's quite a bit of the green stuff. In one spot, the rear right, it was actually dripping a little while the car was in high with the engine off. It stopped after a while. Images are clickable.

Rusty pipes, in the middle at the rear

Rear right

At the front (what is this thing anyway? Accumulator sphere attached to it, is this all it does? What's this round plastic thing?)


I also wanted to change the rear arm bearings today, but unfortunately they weren't in stock and they'll probably arrive next week, when I will get another chance to put the BX on a lift and do the work at the said garage. Do you have any suggestions/concerns about these pictures? Should I get ready for some major leakage? Also, I didn't see any hydraulic piping for sale in the online shop where I usually buy spare parts. Are they only available from citroen (apart from bare piping, if you have a bending tool)? If possible, I'd prefer to do any jobs on the hydraulics _before_ all of the LHM gets spilled on the driveway while thousands of miles away from home

[Aerodynamica]

Hi mate,

I'll admit I'm not sure what's going on in picture 2. but it 'looks' like it's leaking from the rear suspension cylinder vent line. If it's leaking there (as it did on my CX) then too much LHM is getting out from the cylinder and into the rubber cylinder gaiter. On my CX it was simply due to the clip being broken. but it could be due to serious leakage of the strut - dos the rear suspension ink low quickly?

At the front (what is this thing anyway? Accumulator sphere attached to it, is this all it does? What's this round plastic thing?)

Well, the thing the accumulator screws into is the Pressure Regulator - it maintains the hydraulic pressure at 170-175 bar. (KPa) regardless of engine speed. To do this, it has to dump a lot of the LHM supplied by the hydraulic pump. Quite often the return pipes of the dumped LHM can leak.

It's possible too that the O ring seal of the accumulator is leaking.

Also, the pressure regulator could leak at the other end.

None of these look too bad but if they were any worse it could be a problem.

[Aerodynamica]

What's this round plastic thing?

this is the housing for the spring that seats the valve for the cut out setting of the pressure regulator - it's not unknown to leak as it's made from plastic.

[DLM]

Picture 2, if it's the right-hand side of the car viewed from the rear, could be the problem I had on someone else's BX a while back, if the lhm's dripping down from above the rear subframe tube.

The right-hand pipe in the picture is the leakback return pipe, while the left-hand one is the air vent pipe for equalising pressure in the cylinder boot. The vent pipe just pushes into a hole on the bottom of the subframe tube, as pictured.

The 5.5mm clear plastic return pipe meets its counterpart from the other rear cylinder at a rubberised plastic t-piece above the rear subframe, from which a third piece of same-pattern pipe runs forward to the octopus.

You'll get a characteristic "leak from above" if that t-piece splits or decays with age, or one of the pipes becomes detached (they're just a push-fit). Space is a bit tight for working between the subframe and bodywork there, so I dropped the rear subframe a couple of cms to get access.

If it's the t-piece the replacement part from Citroen is upwards of £10, maybe more, but we fixed it using a standard brass plumbing tee with small olives pushed onto the plastic pipes to make the seal.

[TB2]

Interesting, Graeme, David. I'll replace the rear arm bearings in a few days, with those off, I guess I'll have a much better view of the tubing at the rear right. I'll see if it's the T piece or the suspension cylinder. The suspension is pretty stable though, doesn't sink quickly or anything. With the car on the lift, I'd say it lost about 30 drops of LHM over a time of half an hour.

Thanks for the input.